Environmental and occupational lung disease maybe caused by a number of organic agents. While the source of the agents may be know, it is often difficult to identify and characterize the definitive component (s). Pigeon breeders disease is an excellent model for hypersensitivity pneumonitis since the community of pigeon breeders is very accessible and while all may be exposed to the causative agent, only 5-10 percent may develop the disease. In addition, the etiologic agent, the droppings of pigeons, is easily obtained and abundant although the coponent of pigeon droppings associated with the allergic state has not been identified. Recent findings in our laboratory appear to implicate a single antigenic component since symptomatic pigeon breeders produce antibody against it while asymptomatics do not. The aims of the proposal are to isolate this component by biochemical procedures involving chromatography and electrophoresis. It will then be characterized according to chemical and physical properties. The immunological properties will be studies by in vitro and in vivo tests with pigeon breeders. These will include antibody titers, cellular response, skin tests and provocation tests. We will also study the distribution of this antigen, both geographical and biological. To carry out this phase of the research, we will first prepare antisera in rabbits to the isolated antigen. With specific antisera we will test the pigeon droppings obtained from several coops in the Milwaukee area. These studies will indicate if eposure to this antigen may in some way be related to the development of disease. The biological origin of the antigen will also be studied. We will determine if it is a pigeon or microbial component. The ultimate aims will be to determine the exact origin of this apparently disease specific antigen. Finally, additional studies will be carried out to determine if any other disease specific antigens exist in pigeon droppings. This will be done by crossed isoelectric focusing and affinity chromatography on both buffer soluble and detergent soluble extracts of pigeon droppings usning pigeon breeders serum and peripheral blood lymphocytes.